I looked at the chinese lunar calendar for my babies. I did not use it on my first two, but my last i did because i had 2 girls and really wanted a boy. But- it was right on my girls too, my age and my month of conception made me having girls. Here is a link for that. People have had real good luck with this.
Chinese Lunar Calendar
And here is another link of ways to increase your chances of having a girl! Good Luck!!
How To Conceive a Girl